Is Mitochondria An Organelle? 7 Facts You Should Know

Mitochondria are the transducer of energy currency of the cell. ATP is the form of chemical energy required for cellular metabolism. Let us see if mitochondria is an organelle.

Mitochondria are an organelle bounded by two membranes i.e., an inner membrane and an outer membrane having grooves known as cristae.

Billion years ago, mitochondrion was an independent organism and is capable of performing all other cellular activities on its own. But due to some climate changes, they get incorporated by some eucaryotic cells, and after that, are known as semi-autonomous cell organelles.

Let us focus on, in what circumstances mitochondria became an organelle, why it is important to the cell, where it is found, what do they perform and many more questions in this article.

How mitochondria are considered as an organelle?

Mitochondria and chloroplast are evolved from the endosymbionts and have their genome to control the whole process of survival. Let us see how it is considered an organelle.

Mitochondria are to be considered as an organelle as some procaryotes engulf them during evolution. Listed below are some more reasons on how mitochondria are considered as an organelle:

  • A mitochondrion has to associate with the endoplasmic reticulum, peroxisomes and other cell organelles for performing some vital functions.
  • At some point, mitochondria are dependent on the cellular compartments for signal transduction, energy intake, cellular apoptosis and other biochemical reactions.
  • According to “The Endosymbiotic Theory”, an anaerobic bacterium swallowed the aerobic one but is unable to digest it completely.
  • So they have a symbiotic relationship, in which both the organism gets benefitted.
  • Later this new member was known to be an organelle.
is mitochondria an organelle
Image credit: Wikimedia commons

Why mitochondria are the most important organelle?

Mitochondria can divide individually without coupling with the nucleus. Let us explore why it is considered as the most important organelle.

Listed below are some factors which shows why mitochondria is considered as the most important organelle:

  • Mitochondria are the most important organelle because they are the prime source of energy for all the plant and animal cells.
  • They synthesise the energy currency, ATP through oxidative phosphorylation to drive all the cellular metabolism. That is why it is termed as the powerhouse of the cell.
  • Mitochondria is also important in many other ways like the involvement in ion homeostasis, activating some respiratory enzymes, provide the site for oxalic-acetic acid metabolism.
  • They tend to cause programmed cell death.
  • They are the storage tanks for calcium ions used in the contraction of muscles because they are the second most important messenger of the cell and can also regulate signal transduction pathways.
Mitochondrion structure
Well-labelled diagram of mitochondria
Image credit: Wikimedia commons

What organelle are mitochondria found in?

All the organelles like the nucleus, mitochondria, chloroplast, vacuoles, centrioles etc. are dissolved in the matrix. Let us find in which organelle are mitochondria found in.

Mitochondria are found in the cytoplasm. Here, this matrix acts as an absorber for the organelles and also provides a transportation medium for ions and other nutrients.

Cytoplasm holds the components of mitochondria and protects them from damage and also provides mechanical support. It also helps in gaseous exchange and in carrying out glycogenesis. They possess specific enzymes and proteins involved in carbohydrate metabolism.

What is the function of the mitochondria as an organelle

There are many functions performed by mitochondria like cholesterol metabolism and contribution to the synthesis of hormones like oestrogen and testosterone. Let us see more.

The major function of mitochondria is the production of energy in the form of ATPs at the inner mitochondrial membrane via Krebs’s cycle after glycolysis.

This process occurrs in the presence of oxygen and is also known as cellular respiration in which one molecule of glucose breaks into the 2-C compound and undergoes the citric-acid cycle to produce heat and energy. The membranes contain many enzymes and numerous transport systems for the import of metabolites via a chemiosmotic gradient.

is mitochondria an organelle
Flow chart showing the production of energy through multiple steps via mitochondria.
Image credit: Wikimedia commons

Which organelle is first – mitochondria or chloroplast?

Mitochondria or chloroplast are semi-autonomous cell organelles and evolved from free-living organisms to cellular compartments. Let us find out which of the two evolved first.

Mitochondria is the first to be evolved. At that time, a eucaryotic host intakes a cyanobacterial, aerobic bacterium. After years of evolution, they became an essential organelle in a eucaryotic cell.

As per the symbiogenesis theory, they lose their independence and get developed from cyanobacteria and proteobacteria and the evolution of mitochondria was preceded by chloroplast. They are simple in structure with a lot of bacterial similarities.


Mitochondria are believed to be a good example of evolution and have been performing multiple functions inside the cell. This proves itself as a great source of heat and energy generator.

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